git: d6132e2117b7 - stable/13 - cache: improve vnode vs name assertion in cache_enter_time

From: Mateusz Guzik <mjg_at_FreeBSD.org>
Date: Sat, 05 Mar 2022 19:56:55 UTC
The branch stable/13 has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=d6132e2117b7f035a3d73b5cbb34d609aa58f212

commit d6132e2117b7f035a3d73b5cbb34d609aa58f212
Author:     Mateusz Guzik <mjg@FreeBSD.org>
AuthorDate: 2022-02-09 20:41:24 +0000
Commit:     Mateusz Guzik <mjg@FreeBSD.org>
CommitDate: 2022-03-05 19:53:46 +0000

    cache: improve vnode vs name assertion in cache_enter_time
    
    (cherry picked from commit 1d65a9b47eab75f12fcb5cc7547a69441ef764a3)
---
 sys/kern/vfs_cache.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 780b5003749b..52ed0756db25 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -2387,18 +2387,21 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp,
 	KASSERT(cnp->cn_namelen <= NAME_MAX,
 	    ("%s: passed len %ld exceeds NAME_MAX (%d)", __func__, cnp->cn_namelen,
 	    NAME_MAX));
-#ifdef notyet
-	/*
-	 * Not everything doing this is weeded out yet.
-	 */
-	VNPASS(dvp != vp, dvp);
-#endif
 	VNPASS(!VN_IS_DOOMED(dvp), dvp);
 	VNPASS(dvp->v_type != VNON, dvp);
 	if (vp != NULL) {
 		VNPASS(!VN_IS_DOOMED(vp), vp);
 		VNPASS(vp->v_type != VNON, vp);
 	}
+	if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
+		KASSERT(dvp == vp,
+		    ("%s: different vnodes for dot entry (%p; %p)\n", __func__,
+		    dvp, vp));
+	} else {
+		KASSERT(dvp != vp,
+		    ("%s: same vnode for non-dot entry [%s] (%p)\n", __func__,
+		    cnp->cn_nameptr, dvp));
+	}
 
 #ifdef DEBUG_CACHE
 	if (__predict_false(!doingcache))